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Consciousness lost and found: subjective experiences in an unresponsive state
Valdas Noreika1, Leila Jylhänkangas, Levente Móró
1Centre for Cognitive Neuroscience, Department of Psychology, University of Turku, 20014 Turku, Finland. valnor@utu.fi
Brain and Cognition
|October 12, 2011
Summary
Even when unresponsive, individuals may have subjective experiences during anesthesia. Post-anesthesia interviews are crucial for understanding consciousness during sedation.
Area of Science:
- Neuroscience
- Anesthesiology
- Philosophy of Mind
Background:
- Anesthetic-induced neural changes are used to study consciousness.
- The definition of consciousness as "responsiveness" may overlook subjective experiences in unresponsive individuals.
Purpose of the Study:
- To investigate subjective experiences during induced unresponsiveness.
- To analyze reports of consciousness under sedation with dexmedetomidine, propofol, sevoflurane, or xenon.
Main Methods:
- Participants underwent sedation and loss of responsiveness in a nonsurgical setting.
- Subjective experiences were assessed via post-recovery interviews.
- Anesthesia depth was monitored using electroencephalography (EEG).
Main Results:
- Participants reported subjective experiences in nearly 60% of sessions.
- Dexmedetomidine-induced experiences correlated with shallower "depth of sedation" on EEG.
- Subjective experiences can occur despite clinical unresponsiveness.
Conclusions:
- Clinical definitions of consciousness based solely on responsiveness are insufficient.
- Investigating phenomenal consciousness under anesthesia requires assessing subjective states of unresponsive individuals.
- Post-recovery interviews are essential for comprehensive consciousness research during sedation.
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